Tapentadol is central analgesic with a dual action mechanism developed by Johnson & Johnson, since it is both the μ-type opioid receptor agonist and norepinephrine reuptake inhibitor, up to now it is the first single-molecule drug which has both above pharmacological effects. It was approved for marketing on Nov. 21, 2008 by the U.S. Food and Drug Administration, for the treatment of moderate to severe acute pain. Studies show that tapentadol is independent of metabolism activation and has no active metabolite; moreover, it has curative effect on all of the acute, inflammatory and chronic neuropathic pain models, and its effectiveness is between morphine and tramadol; in addition, the satisfactory plasma concentration can be obtained by both intravenous and oral administration of tapentadol, it is not easier to cause analgesic tolerance and physical dependence than morphine, and its clinical application shows mild side effects and well tolerance. Its chemical name is: (+)-(1R,2R)-3-(3-dimethylamino-1-ethyl-2-methylpropyl)-phenol, whose structure is represented by the following formula (II):

It is recorded in European Patent No. EP693475 a method for preparing compound (II) from 3-pentanone through the Mannich reaction, Grignard reaction, crystallization to separate diastereoisomer, column chromatography to separate diastereoisomer, chloridization, elimination and demethylation reaction, the method is shown as Reaction Scheme 1:

It is recorded in European Patent No. EP2049464 and U.S. Patent No. US2009326271 a method for preparing compound (II) from 3′-benzyloxyphenyl ethyl ketone through Mannich reaction, chiral separation, Grignard reaction, dehydration, and debenzylation together with stereoselective hydrogenation, the method is shown as Reaction Scheme 2:

It is recorded in European Patent No. EP2046724 a method for preparing the hydrochloride of compound (II) from 3′-methoxyphenyl ethyl ketone through Mannich reaction, chiral separation, Grignard reaction, dehydration, stereoselective hydrogenation, demethylation reaction, and directly adding hydrochloric acid without separation, the method is shown as Reaction Scheme 3:

It is recorded in European Patent No. EP2046726 and U.S. Patent No. US2009312578 an improved method of the dehydration reaction in the above Reaction Scheme 3, that is, after dehydration using trifluoroacetic anhydride or acylating hydroxy compound, hydrogenation and deprivation are performed, the method is shown as Reaction Scheme 4:

The existing synthesis methods of tapentadol adopt the column chromatography or resolution methods, which have a high cost and low yield, and are not suitable for industrial production. Therefore, it is eager to find a method which has simple process, high yield, low cost and is suitable for industrial production.